Sometimes it's impossible to avoid the need for Windows. In the past I've used Virtual PC on the Mac, but I've been looking for a good free alternative. I think I've found one. Qemu is a generic open source processor emulator, and Q is a "feature packed cocoa port".
After a short time installing, I got a copy of Windows 98 working. I felt almost nostalgic seeing the first screen on boot. Was it really 8 years ago? Doesn't time fly ...
Anyway, if you're a Mac user who sometimes needs to run Windows software, take a look at Q. It's not astoundingly fast, but it's good enough.